import java.awt.Point;


public class Vector {
	int x;
	int y;
	float d;
	public Vector (int x0, int y0){
		x = x0; 
		y = y0;
		d = getLen();
	}
	public Vector (Point pSt, Point pEn) {
		x = pEn.x-pSt.x;
		y = pEn.y-pSt.y;
		d = getLen();

	}
	public Vector revert () { return new Vector (-(this.x),-(this.y));}
	public boolean obtuseAngle (Vector v) {
		return this.x * v.x + this.y * v.y < 0;	}
	public float getLen () {return (float) Math.sqrt (Math.pow(x,2) + Math.pow(y,2));}
}
